Robotic Arm (RA)

built by the Jet Propulsion Laboratory, Alliance Spacesystems and Honeybee Robotics

The RA is critical to the operations of the Phoenix lander and is designed to dig trenches, scoop up soil and water ice samples, and deliver these samples to the TEGA and MECA instruments for detailed chemical and geological analysis. Designed similar to a back hoe, the RA can operate with four degrees of freedom: (1) up and down, (2) side to side, (3) back and forth, and (4) rotate around.

The engineering model of the 2.35-m-long Phoenix Robotic Arm (RA) in the Payload Interoperability Testbed at the University of Arizona.. Image Credit: NASA/JPL.

The RA is 2.35 meters (just under 8 ft) long with an elbow joint in the middle, allowing the arm to trench about 0.5m (1.6ft) below the martian surface, deep enough to where scientists believe the water-ice soil interface lies. At the end of the RA is a scoop for digging and acquiring loose soil. On the bottom side of scoop is a scraping blade for scraping hard icy soil and protruding from the backside of the scoop is a circular rasp used for acquiring icy-soil samples by pulverizing the icy soil and ejecting it into the back of the scoop for delivery to TEGA.

The RA was sterilized and encased in a protective bio-barrier prior to final integration on the Lander to prevent contamination of the Martian sub-surface with microbes from Earth.

Development of the RA was a collaborative effort led by Dr. Robert Bonitz. of the Jet Propulsion Laboratory. JPL designed and built the RA control avionics, flight software, bio-barrier, and was responsible for integration and testing of the RA system; Alliance Spacesystems designed and built the arm; and Honeybee Robotics designed and built the scoop and rasp.

Close up of the scoop and other instruments at the end of the RA. Image Credit: NASA/JPL.